When we think of life's major milestone birthdays, 66 isn't necessarily one of them. It certainly doesn't have the same ring as turning 40, 50, 60, or even 65. That said, 66 is an age to celebrate in its own right, especially if you've got retirement on the brain. Here are a few things you should know if you'll be blowing out 66 candles this year.

1. You'll be eligible for your full monthly Social Security benefit

Though your Social Security benefits are based on your 35 highest years of earnings on record, the age at which you file for them will also determine how much you collect from the program each month. If you retire at what's known as your full retirement age, you'll collect the full monthly benefit your earnings history entitles you.

For those born between 1943 and 1954, the Social Security Administration has designated 66 as full retirement age, which means that if you're reaching that milestone this year, you'll be entitled to collect your Social Security benefits in full (whereas if you were to file even a couple of months early, you'd reduce your monthly payments, and quite possibly for life).

Man holding a small, round cake and blowing out the candles


Of course, that doesn't mean you need to rush to file on your birthday, either. In fact, if you delay your benefits past full retirement age, you'll boost them by 8% for each year you hold off up until you turn 70. Therefore, if you're still working by the time you reach 66, you might let those benefits grow a while longer and increase them on a permanent basis.

2. You're already eligible for Medicare

Medicare eligibility kicks in at age 65, so if you haven't yet signed up for coverage, you may want to get moving. Though Medicare Part B, which covers doctor visits, charges enrollees a premium, Part A, which covers hospital stays, is free. That's why it pays to enroll in Part A even if you're still working and have coverage under a group health plan through your employer. That way, Medicare will serve as a secondary payer and possibly pick up the tab in situations where your primary insurer doesn't. That said, you shouldn't sign up for Part A if you're still planning to fund a health savings account, because you can't contribute to one if you have Medicare coverage of any kind.

3. You can work and collect Social Security simultaneously

Many seniors are advised to hold off on filing for Social Security if they're currently working, the logic being that if a steady paycheck is coming in, there's no sense in not growing those benefits. But what if you want those benefits to enjoy your life more while you're relatively young? What if your paycheck is just enough to cover the bills, but your Social Security income will allow you to travel or fulfill other life goals? In that case, you might choose to file for benefits even if you still have a paying job.

Now if you haven't yet reached full retirement age, working and collecting Social Security at the same time means having a portion of those benefits withheld. But once you reach full retirement age, you can earn as much as you'd like and also collect your benefits in full. Therefore, once you turn 66, you can enjoy both income streams without having to worry about ramifications other than not boosting your benefits (which, if you've saved wisely, might not hurt you in retirement).

There's lots to celebrate -- and know -- about turning 66. Keep the above points in mind, especially if retirement is on your radar.